{
    title:  "Compatibility",
    crumbs: [ 
        { 'Reference': '../ref/'} ,
    ],
}
   
            <h1>Compatibility</h1>
            <p>Appweb is provided in two supported versions:</p>
            <ul>
                <li><b>Appweb Development Versions (DEV)</b> &mdash; The goal of DEV versions is ongoing 
                feature development. 
                New features will be issued for DEV versions and APIs will evolve. Appweb 5 is the current DEV version.</li>
                <li><b>Appweb Long Term Support (LTS)</b> &mdash; The goal of LTS versions is stability and compatibility. 
                Bugs and security issues will be fixed, but no feature updates will be issued for LTS versions. 
                Appweb 4.X is head of the LTS stream and it will be maintained with security updates and fixes until 
                the end of 2015.</li>
            </ul>
            <a id="api"></a>
            <h2>API Compatibility</h2>
            <p>In the development stream the Appweb APIs may evolve, and are thus subject to change 
            between minor releases. The Appweb documentation
            provides a <a href="stability.html">Stability Classification</a> for each 
            API group that reflects their stability with respect to forward changes.</p>
            
            <a id="r5"></a>
            <h2>Migrating to Appweb 5</h2>
            <p>Appweb 4 and 5 are highly compatible. Code written for Appweb 4 should migrate to Appweb 5 with few 
            changes required. Appweb 5 does use a newer version of the MakeMe/Bit and Pak tools.</p>
            <p>If you are migrating from Appweb 2 or 3, you should regard Appweb 5.X as a next generation web server.
            You can migrate code from Appweb 2 or 3 to Appweb 5, however, you should anticipate significant refactoring 
            work in the transition.</p>
            <a id="r4"></a>
            <h2>Appweb 4</h2>
            <p>Appweb 4 is an evolutionary release relative to Appweb 3. Many APIs have changed since Appweb 3
            and new APIs have been added for increased functionality. Appweb 4 uses a new memory allocator that 
            does not require a memory context as the first argument to most APIs. So many APIs have changed 
            signature, while the underlying functionality remains largely similar. The memory allocator uses 
            garbage collection and this eliminates the need to manually free up memory. You can migrate code 
            from Appweb 3 to Appweb 4 with refactoring.</p>
            <a id="r2"></a>
            <h2>Appweb 2 and 3</h2>
            <p>Appweb versions 2 and 3 are now officially deprecated. Support is only available under special arrangements
            via custom dev services programs.</p>
            <h2>Standards</h2>
            <p>Appweb supports the following standards:</p>
            <ul>
                <li><a href="http://www.w3.org/Protocols/rfc2616/rfc2616.html">HTTP/1.1</a></li>
                <li><a href="http://www.w3.org/CGI/">CGI 1.1</a></li>
                <li><a href="http://www.ietf.org/rfc/rfc1867.txt">Form-based File Upload in HTML</a></li>
                <li><a href="http://www.ecma-international.org/publications/standards/Ecma-262.htm">ECMA-262 for server
                side JavaScript if using Ejscript</a></li>
            </ul>
